1. Field of the Invention
This invention pertains to an adjustable radial curve radius setting scale for use as an aid in engineering and construction layout and design. The instrument is particularly useful in making curves of any radius. Artists and craftsmen will find this instrument helpful in constructing designs involving circles. The instrument is also useful in the aircraft and ship building industries as well as forming work on construction projects. Instructors will find this instrument to be versatile and useful in instructing students. Handymen will find a variety of uses for this instrument for home and outdoor projects. Even children will enjoy its versatility in constructing circles of any radius.
The instrument may be constructed in various sizes to accommodate projects of all sizes. The instrument components are precisely dimensioned and assembled such that the ruling edge provides extreme accuracy.
The adjustable radial curve radius setting scale is 100 percent accurate throughout its entire length. It is constructed using the principals of chord deflections and radial lines.
2. Statement of the Prior Art
Adjustable curved rulers or scribers are well-known. One such device is described in U.S. Pat. No. 2,798,299. This patent discloses an adjustable curve having a plurality of cylindrical weights attached together by a series of linkages. A flexible metal band is attached to the cylindrical weights in such a fashion that permits it to bend in a curve upon manipulation of the various weights. Another curved ruler is disclosed in U.S. Pat. No. 1,893,690. This tool comprises a flexible body formed of strips or ribbons of steel to which there is attached a flexible ruling edge. On the other hand, the present invention is a lightweight instrument formed of superimposed chords and braces and radial arms connected together by suitable pins so as to permit them to rotate and deflect dependently of each other. A ruling edge is attached in a manner to allow it to bend or flex upon adjustment of the assemblage. A bar scale is pivotably attached at one point to the supporting tangent bar and to the other end to the diagonal braces and radial arms. The other end of the bar scale is slidable through a glideway attached to another point on the tool. A base is provided having at least one guideway whereby radii of particular dimensions may be constructed.
Representative of the prior art, in addition to the above patents, are the following patents.
______________________________________ Patentee U.S. Pat. No. Issue Date ______________________________________ Riegel 20,121 Oct. 29, 1863 Wollenhaupt 219,330 Feb. 21, 1910 P. A. Gagarin 677,349 July 2, 1901 A. Gran J. H. Karlson 989,547 Apr. 11, 1911 W. S. Weston 1,061,345 May 13, 1913 A. E. Hegardt 1,313,482 Aug. 19, 1919 G. J. Nies 1,380,240 May 31, 1921 K. Schmieder 1,797,842 Mar. 24, 1931 W. S. Weston 1,893,690 Jan. 10, 1933 F. D. Hinckelmann 1,900,500 Mar. 7, 1933 F. D. Cooper 2,798,299 July 9, 1957 J. E. Hoyle 3,134,176 May 26, 1964 Toshio Yoshioka 3,388,475 June 18, 1968 Debeaux 3,781,995 Jan. 1, 1974 ______________________________________